Best I can figure it was caused by insufficient strength of the wall of the seat tube

Or the DIY mods.. You definitely won that one with a $50 replacement.

Looking to burn up build kits on potentially 3 frames.
Key parts are I've 3 trunion shocks needing a home and at the least I'd like an XC build and a Trail Build
1 x Nude 165x45 (Spark)
1 x DPS 185x55 (Genius)
1 x X2 205x65 (ransom)
I figure there'll be a saving on shipping to do all 3 from the same supplier.

So, whats going to give me the best solution;
Carbonda (936+1001+1002) or
Lightcarbon (917 or 958 + 947 + skip the 205shock)

Speed of shipping to Canada might be the deal maker
Any other suggestions welcomed.
ta

remedy7, so you know, next time you paint, montana gold wet sands pretty nicely. You could've knocked down that texture that those Montana cans give before going to the spraymax top coat

Enter

I used a can of spraymax 2k epoxy primer on my knife stripped frame. 3 light coats of montana gold color coat (2 cans), another couple of different color coats after masking for decals which was 1/2+ can, then 1.5 cans of 2k epoxy matt clear to finish.
Thats 5 x 300g cans of paint, removing the overspray on the floor and in the filter media, there's almost no way that's only going to have added 150g of weight. I'd guess closer to an added pound of weight
With your huge layer buildup, I wonder what kind of weight of paint you have.

It's clearly cracked, not sure why eddy needs the frame to see that.
He would want the frame to see if it's poor machining though or hadn't been through QC at that finishing stage.
Otherwise, wrong size seatpost or the easy out of saying it was ridden/tested with insufficient insertion.

The  way you said installed to mark a cut point  reminded me of a friend who put his seatpost in to mark for the cut. Set his height, marked it, added the "minimum insertion depth" measurement as printed on the bottom of the post. Cut it, reinstalled it, sat on it and snapped the seat tube. Proper brain fart on his part.
Fortunately it was the relative early days of carbon and a 34.9mm seat tube. We epoxied in a shim and he ran a 31.6 post successfully.
With a fixed post, I'd insert it to its bottom out position,  figure how much lower I need it to be which equals how much I want to take off, remove the post then measure up from the end of the post.

I personally would repair that crack at home, but I have all the materials to do it.

Looks like a repair patch over a void or deficiency.

You're seeing a few frames now using "flex stays" rather than these physical pivots.
The flex stays are designed to provide the small angular change between seat stays and chainstays that pivots also provide.
Bearing based pivots tend to still be used on longer travel bikes where weight is less of an issue than a light xc bike which are trending into the flex stays design.
People used to moan about bushings.being used in that application rather than bearings, but as there's often so little rotation there anyways bearings could be considered overkill